The laundry industry has been trying to develop ways that minimise the contact between incompatible detergent ingredients during the manufacturing, transport and storage of detergent products prior to addition to the washing cycle.
One such way is the development of a multi-compartment water-soluble detergent pouch. Incompatible detergent ingredients are comprised by different compartments of said pouch in such a manner so that they do not come into contact with each other until said pouch dissolves or disintegrates in water during the washing cycle.
Examples of these multi-compartment pouches are described in U.S. Pat. No. 4,973,416 and U.S. Pat. No. 5,224,601. The use of compartments which can contain different detergent ingredients is designed to overcome the problems associated with the storage of incompatible detergent ingredients, since said ingredients do not come into contact during storage as they are in separate compartments.
The inventors have found that there is a risk of detergent ingredients leaking from multi-compartment pouches, in addition the inventors have found that detergent ingredients are more likely to leak from the seals of a multi-compartment pouch, especially when the compartments are sealed simultaneously, due to the poor seal strength. The risk of leakage is greater when one of the compartments comprises a liquid.
Furthermore, the inventors have found that if the compartments are sealed simultaneously, a process which requires unsealed compartments being in relatively close proximity, there is a risk that ingredients may leak from one unsealed compartment to another during the sealing process, due the lack of a seal to prevent the exchange of ingredients between the two compartments during the early stages of the sealing process. This is especially applicable if one or more of the ingredients is a liquid.
Herein, the inventors have found that by using a pre-sealed water-soluble compartment to close an unsealed compartment, thus forming a multi-compartment water-soluble pouch, said multi-compartment water-soluble pouch is more stable having a reduced risk of ingredients leaking from the seals of said pouch both during the manufacturing and storage of the pouch. This is due to the multiple seal that is formed by the above closing process. This is especially applicable if the pre-sealed water-soluble compartment comprises a liquid.